Light-emitting device

Abstract

The present invention is a light-emitting device that has a peak wavelength in at least a region exceeding 700 nm by being excited by light from a light source. A light-emitting device comprises: a solid light source that emits light having a peak wavelength in a range of 480 nm or less, and a fluorescent film covering the solid light source and containing at least one fluorescent substance, the fluorescent film containing: at least one near-infrared fluorescent substance that has a peak wavelength in a range exceeding 700 nm by being excited by light from the solid light source, and the full width at half maximum of the light-emitting spectrum in the range including the peak wavelength is 100 nm or more.

Description

Technical Field

[0001] The present invention relates to a light emitting device. Background Art

[0002] In recent years, various lighting, led by household lighting, is rapidly replacing halogen lamps with light-emitting diodes (LEDs), which can achieve long life and miniaturization. However, most of the light sources used in industrial machines such as spectroscopic analysis devices still use halogen lamps instead of LEDs. The main reason for this is that it is believed that it is difficult for previous LEDs to meet the following characteristics required by light sources for industrial machines: stable luminous spectrum distribution under a wide band, and wavelength shift caused by temperature changes that are not easy to occur. Patent document 1 records: A multilayer film for a light-emitting device containing two or more phosphors including a red phosphor and a green phosphor, wherein the phosphor contained in each phosphor layer is one type, and is arranged in the order from the phosphor layer containing a long-light-emitting wavelength phosphor to the phosphor layer containing a short-light-emitting wavelength phosphor, thereby increasing the total luminous flux of the light-emitting device.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-130459. Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, conventional light-emitting devices are light-emitting devices intended for lighting purposes, and therefore have a peak wavelength (peak wavelength) of 700 nm or less on the high-wavelength side, which is insufficient as a light source for industrial machinery that is required to emit light with a peak wavelength in the near-infrared region exceeding 700 nm.

[0008] An object of the present invention is to provide a light-emitting device having a peak wavelength in at least a region exceeding 700 nm when excited by light from a light source.

[0009] Technical solutions to problems

[0010] The present invention relates to the following contents.

[0011] [1] A light-emitting device comprising at least: a solid light source that emits light having a peak wavelength in a range below 480 nm, and a fluorescent film that covers the solid light source and contains at least one fluorescent substance, wherein the fluorescent film contains: at least one near-infrared fluorescent substance that is excited by light from the solid light source and emits light having a peak wavelength in a range exceeding 700 nm and a full width at half maximum of a light-emitting spectrum in a range including the peak wavelength of 100 nm or more.

[0012] [2] The light-emitting device of [1] has a continuous light emission spectrum at least in the range of 400 nm to 1000 nm.

[0013] [3] A light-emitting device as described in [1] or [2], wherein the fluorescent film further contains: at least one visible light phosphor which is excited by the light from the solid light source to emit light having a peak wavelength in the range of greater than 350 nm and less than 700 nm.

[0014] [4] A light-emitting device as in [3], wherein the fluorescent film comprises one or more visible light phosphors A, B and C as the visible light phosphors, respectively; the visible light phosphor A is excited by the light from the solid light source to emit light having a peak wavelength in the range of 350 nm to less than 430 nm; the visible light phosphor B is excited by the light from the solid light source to emit light having a peak wavelength in the range of 430 nm to less than 500 nm; and the visible light phosphor C is excited by the light from the solid light source to emit light having a peak wavelength in the range of 500 nm to 700 nm.

[0015] [5] The light-emitting device of [4], wherein the fluorescent film is formed of two or more layers, and the visible light phosphors A and B are contained in different layers.

[0016] [6] A light-emitting device as in [4] or [5], wherein the fluorescent film is formed by two or more layers containing different types of the fluorescent material, and the two or more layers are stacked in the direction of travel of light from the solid light source in the order from a layer containing a fluorescent material with a longer peak wavelength to a layer containing a fluorescent material with a shorter peak wavelength.

[0017] [7] The light-emitting device of [5] or [6], wherein the number of types of the phosphor contained in each layer of the fluorescent film is 1 or more and 3 or less.

[0018] [8] The light-emitting device of [4], wherein the fluorescent film has two or more regions containing different types of the fluorescent material on the same surface.

[0019] [9] A light-emitting device as in [8], wherein the two or more regions of different types of phosphors include at least: a region containing the near-infrared phosphor, and a region containing the visible light phosphor.

[0020]

[10] The light-emitting device according to any one of [1] to [9], comprising two or more of the solid-state light sources.

[0021]

[11] The light-emitting device of any one of [1] to

[10] , wherein the solid light source is at least one selected from a light-emitting diode, a laser diode, and an organic electroluminescent element.

[0022]

[12] The light-emitting device of any one of [1] to

[11] , wherein the near-infrared phosphor contains divalent europium ions.

[0023]

[13] The light-emitting device according to any one of [1] to

[12] , wherein the near-infrared phosphor has a composition represented by the following formula (I):

[0024] Li a Sr b La c Si d N e Eu f ...(I)

[0025] (Among them, a~f are numbers satisfying a+b+c+d+e+f=100, 0≤a≤8.22, 0.22≤b≤17.33, 1.12≤c≤11.36, 22.41≤d≤38.09, 49.47≤e≤56.09, 0.88≤f≤1.01).

[0026]

[14] A fluorescent film comprising: at least one near-infrared phosphor which, by emitting light having a peak wavelength in a range exceeding 700 nm and having a half-width at half maximum of 100 nm or more, emits light having a peak wavelength in a range exceeding 700 nm and having a luminescence spectrum in a range including the peak wavelength of 100 nm or more; and at least one visible light phosphor which, by emitting light having a peak wavelength in a range exceeding 350 nm and below 700 nm, emits light having a peak wavelength in a range exceeding 480 nm.

[0027] Effects of the Invention

[0028] According to the present invention, it is possible to provide a light-emitting device having a peak wavelength at least in a region exceeding 700 nm due to excitation by light from a light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1The diagram schematically shows the structure of a light emitting device according to one embodiment, (A) is a plan view, and (B) is a side view.

[0030] Figure 2 It is an explanatory diagram showing an example of stacking of solid-state light sources and fluorescent films.

[0031] Figure 3 These are the emission spectra of near-infrared phosphors P1 to P7 used in the examples. A shows the emission spectra of near-infrared phosphors P1 and P2. B shows the emission spectra of near-infrared phosphors P3 and P4. C shows the emission spectra of near-infrared phosphors P5 to P7.

[0032] Figure 4 : These are the emission spectra of near-infrared phosphors P8 to P14 used in Examples. D shows the emission spectra of near-infrared phosphors P8 and P9. E shows the emission spectra of near-infrared phosphors P10 and P11. F shows the emission spectra of near-infrared phosphors P12 to 14.

[0033] Figure 5 This is the emission spectrum of the near-infrared phosphor P8 used in the examples.

[0034] Figure 6 It is the luminous spectrum of the light-emitting device of Examples 1 and 3.

[0035] Figure 7 This is the emission spectrum of the light-emitting device of Example 2.

[0036] Figure 8 These are the emission spectra of the light-emitting devices of Example 1 and Comparative Examples 1 and 2.

[0037] Fig. 9 It is a schematic plan view showing a configuration example of a light emitting device according to a first variant.

[0038] Fig.10 It is a schematic side view showing a configuration example of a light emitting device according to a first variation.

[0039] Fig.11 It is a schematic plan view showing a configuration example of a light emitting device according to a second variant.

[0040] Fig.12 It is a schematic plan view showing a configuration example of a light emitting device according to a second variant. DETAILED DESCRIPTION

[0041] An embodiment of the present invention will be described in detail below. The present invention is not limited to the following embodiment, and can be implemented by adding appropriate changes within a range that does not hinder the effects of the present invention.

[0042] <First Embodiment>

[0043] [Light-emitting device]

[0044] Figure 1 : Shown in the figure are a schematic plan view and a side view showing the structure of a light emitting device according to one embodiment. Figure 2 : An example of stacking of a solid-state light source and a fluorescent film is shown. Figure 1 , 2 The light emitting device 10 shown in the figure comprises: a solid light source 2 placed in a package 1, and a fluorescent film 3 covering the solid light source 2. The package 1 is composed of a cup-shaped base having a concave portion, the solid light source 2 is provided on the bottom surface of the concave portion, and the opening portion of the concave portion is covered by the fluorescent film 3. It should be noted that Figure 1 (A) The fluorescent film 3 is omitted. As a substrate constituting the package 1, a surface mounting package (SMD package) using a resin plate, a ceramic plate, etc. or a chip-on-board substrate (COB substrate) can be used. The solid light source 2 is bonded to the package 1 using a die-attachment agent such as a silver paste not shown, and is electrically connected to the package 1 through a wire 4 containing gold or the like in a manner such that the positive and negative electrodes of the solid light source 2 are connected to the electrode pads 5 of the positive and negative electrodes of the package 1. It should be noted that in the case of flip chip installation, a protruding terminal using a conductive component can be used instead of the wire 4 for electrical connection. On the upper side of the solid light source 2, a fluorescent film 3 is provided at a predetermined space from the upper surface of the solid light source 2 to cover the opening of the recess of the package 1 and to be parallel to the upper surface of the solid light source 2. Thus, the fluorescent film 3 is provided to cover the entire solid light source 2 and the main surface intersects perpendicularly with the light from the solid light source 2.

[0045] Figure 2 In the embodiment, the fluorescent film 3 is composed of three layers, but it can also be a single layer or any number of layers of two or more layers. The details of the layer structure are described later. In the case where the fluorescent film 3 is formed by a plurality of layers (two or more layers), each layer is stacked in the traveling direction of the light from the solid light source 2. Figure 1 In the embodiment, the fluorescent film 3 is provided with a predetermined space between it and the upper surface of the solid light source, and the space can be filled with an inert gas, a resin, a transparent member such as glass, etc. In addition, the fluorescent film 3 can be provided in contact with the solid light source 2.

[0046] like Figure 1 As shown, an electrostatic protection element 6 such as a Zener diode or an ESD element may be connected to the electrode pad 5 by a wire 4 in parallel with the solid light source 2 as needed.

[0047] (Solid Light Source)

[0048] The solid light source is a solid light source that emits light with a peak wavelength in a range below 480nm. The solid light source can also be set to a solid light source that emits light with a peak wavelength in a range below 450nm or below 410nm. The lower limit of the range of the peak wavelength of the light emitted by the solid light source is not particularly limited, and can be set to above 260nm, above 330nm, or above 350nm. It should be noted that in this specification, unless otherwise specified, the term "peak wavelength" refers to the wavelength at which the spectroscopic luminescence spectrum shows a peak, and the wavelength of the maximum intensity therein is referred to as the "maximum peak wavelength". By using a solid light source that emits light with a peak wavelength in the above range, various phosphors described later can be excited. In addition, the luminescence spectrum of a solid light source can generally be considered to have a half-width of more than 10 nm, and the luminescence spectrum adopts an intensity distribution according to a Gaussian function, so the width of the cut-off wavelength (for example, the wavelength when the fluorescence intensity is lower than 1.5% of the intensity at the maximum peak wavelength) (the interval between the cut-off wavelength on the short wavelength side and the cut-off wavelength on the long wavelength side) is more than 20 nm. Therefore, for example, a solid light source that emits light with a peak wavelength in the range below 400 nm can be used, thereby enabling a light-emitting device having a luminescence spectrum in the ultraviolet region below 380 nm.

[0049] As a solid light source, for example, at least one selected from a light emitting diode (LED), a laser diode (LD), and an organic electroluminescent element (organic EL element) can be used. As LED or LD, for example, an LED or LD emitting ultraviolet to purple light of InGaN series, GaN series, AlGaN series, etc. can be cited. As an organic EL element, for example, there can be mentioned an organic EL element in which the light-emitting layer contains one or more blue light-emitting materials selected from the following compounds having an aromatic group in the skeleton: naphthalene, distyrylarylene, oxazole, isoxazole, oxadiazole, imidazole, carbazole, pyrazole, pyrrole, furan, furazan, benzofuran, isobenzofuran, fluorene, pyridine, pyran, benzopyran, pyrazine, pyrimidine, pyridazine, bipyridine, quinoxaline, xanthene, phenazine, phenoxazine, dibenzodioxin, dibenzofuran, and their derivatives.

[0050] (Fluorescent film)

[0051] The fluorescent film is arranged in a manner covering the solid light source and contains at least one fluorescent substance. The fluorescent film can be composed of a single layer or two or more layers. The fluorescent film contains: at least one near-infrared fluorescent substance (hereinafter also referred to as "near-infrared fluorescent substance"), which is excited by light from the solid light source and emits light having a peak wavelength (preferably a maximum peak wavelength) in a range exceeding 700 nm, preferably in a range exceeding 750 nm, and the full width at half maximum (FWHM) of the emission spectrum is 100 nm or more, preferably 120 nm or more, more preferably 150 nm or more, and particularly preferably 200 nm or more.

[0052] It should be noted that, in this specification, the term "near-infrared phosphor" refers to "a phosphor that is excited by light from a solid light source and emits light having a peak wavelength (preferably a maximum peak wavelength) in a range exceeding 700 nm, and a full width at half maximum of a light emission spectrum in a range including the peak wavelength of 100 nm or more". In general, the term "near infrared" is used as a term to refer to a wavelength range of about 780 nm to 3000 nm. The near-infrared phosphor used in this embodiment can be considered to have a peak wavelength in a range exceeding 700 nm and a full width at half maximum of a light emission spectrum in a range including the peak wavelength of 100 nm or more, and the light emission spectrum adopts an intensity distribution according to a Gaussian function, so the width of the cut-off wavelength (for example, the wavelength when the fluorescence intensity is less than 1.5% of the intensity at the maximum peak wavelength) (the interval between the short-wavelength side cut-off wavelength and the long-wavelength side cut-off wavelength) is 200 nm or more, so that the spectrum can be presented at least in a wavelength range exceeding 780 nm, which is not contradictory from a general meaning.

[0053] Because it contains "a near-infrared phosphor that is excited by light from a solid light source to form a wide peak with a peak wavelength in a range exceeding 700nm, and the half-width of the emission spectrum is 50nm or more, especially 100nm or more", it is possible to produce a light-emitting device that has a certain intensity and a wide peak wavelength in the near-infrared region by the above-mentioned excitation by the light from the light source. In addition, in combination with the above-mentioned solid light source and the visible light phosphor that can be contained as needed as described later, it is possible to produce a light-emitting device having a broadband emission spectrum from the ultraviolet region to the near-infrared region. It should be noted that the near-infrared phosphor only needs to have a peak wavelength in a range exceeding 700nm, preferably in a range exceeding 750nm, and may also have a peak wavelength in other ranges. For example, the near-infrared phosphor may also be constructed in a manner having a peak wavelength in a range exceeding 600nm and below 700nm and in a range exceeding 700nm.

[0054] according to Figure 5 , illustrating an example of the emission spectrum of a near-infrared phosphor. Figure 5 This is the emission spectrum of the near-infrared phosphor P8 used in the examples described below (light source: xenon lamp with spectroscopy at 370 nm). Figure 5 As shown, this near-infrared phosphor has peak wavelengths at 680±3nm and 776±3nm. That is, this near-infrared phosphor has a peak wavelength in the range of more than 700nm. The half-widths of the emission spectra are 113nm and 209nm respectively. The peaks of the two overlap, and the cutoff wavelength of the emission spectrum containing both (for example, the wavelength when the fluorescence intensity is less than 1.5% of the intensity at 800nm) is 540±3nm on the short wavelength side and 1200±3nm on the long wavelength side. It should be noted that the emission spectrum of the near-infrared phosphor only needs to have a peak wavelength in the range of more than 700nm, and is not limited to Figure 5 The luminescence spectrum shown is the same waveform.

[0055] For a light-emitting device composed of a fluorescent film using this near-infrared fluorescent material (excluding a fluorescent film of a visible light fluorescent material described later) and the above-mentioned solid light source, the intensity balance is arbitrary, but Figure 5 At approximately the same wavelength, there is a peak wavelength.

[0056] As a near-infrared phosphor, there is no particular limitation as long as it is a phosphor having a peak wavelength within the above range, and examples thereof include europium or cerium activated nitride or oxynitride phosphors. These are luminescent materials generated by transitions between 5d and 4f, and have a wide half-width, and are therefore preferred. In particular, a phosphor to which divalent europium (divalent europium ion) is added has a wide half-width and high luminous intensity, and is therefore more preferred.

[0057] Examples of europium or cerium activated nitride or oxynitride phosphors include nitride phosphors having a matrix crystal made of nitrides of one or more metals selected from the group consisting of Li, Sr, La, and Si, and containing europium as an activator in the matrix crystal.

[0058] When the near-infrared phosphor is set to have a composition represented by the following formula (I), the half-width is wide, so it is preferred. When it is set to have a composition of 0.88≤f≤1.01 in the following formula (I), the luminous intensity is high, so it is more preferred.

[0059] Li a Sr b La c Si d N e Eu f ...(I)

[0060] (Among them, a~f are numbers representing a+b+c+d+e+f=100, 0≤a≤8.22, 0.22≤b≤17.33, 1.12≤c≤11.36, 22.41≤d≤38.09, 49.47≤e≤56.09, 0.05≤f≤10).

[0061] The content of the near-infrared phosphor is preferably 5% by mass or more and 50% by mass or less of all phosphors contained in the phosphor film, more preferably 10% by mass or more and 30% by mass or less, and further preferably 15% by mass or more and 25% by mass or less. By setting it within the above range, the light emission of the near-infrared phosphor can be obtained without hindering the light emission of other phosphor layers.

[0062] The fluorescent film may contain, in addition to the above-mentioned near-infrared fluorescent body, at least one visible fluorescent body (hereinafter also referred to as "visible fluorescent body"), which is excited by light from a solid light source and emits light having a peak wavelength (preferably a maximum peak wavelength) in the range of 350 nm to 700 nm. By containing the visible fluorescent body, a light-emitting device having a broadband light emission spectrum covering the ultraviolet region, the visible light region, and the infrared region can be manufactured.

[0063] It should be noted that, in this specification, the term "visible light phosphor" refers to "a phosphor that is excited by light from a solid light source and emits light having a peak wavelength (preferably a maximum peak wavelength) in the range of not less than 350 nm and not more than 700 nm" as described above. In general, the term "visible light" is used as a term referring to a wavelength range of about 380 nm to 780 nm. The visible light phosphor used in the present embodiment has a peak wavelength in the range of not less than 350 nm and not more than 700 nm, and it can generally be considered that the half-maximum full width of the emission spectrum is not less than 50 nm, and the emission spectrum adopts an intensity distribution according to a Gaussian function, so the width of the cut-off wavelength (for example, the wavelength when the fluorescence intensity is less than 1.5% of the intensity at the maximum peak wavelength) (the range of the short-wavelength side cut-off wavelength and the long-wavelength side cut-off wavelength) is not less than 100 nm, so the spectrum can be presented in the entire region of the wavelength range of at least about 380 nm to 780 nm, so there is no contradiction from the general meaning.

[0064] As a visible light phosphor, there is no particular limitation as long as it is a phosphor having a peak wavelength within the above range, and examples thereof include: phosphor A (hereinafter referred to as "visible light phosphor A") which is excited by light from a solid light source and emits light having a peak wavelength within a range of 350 nm to less than 430 nm, phosphor B (hereinafter referred to as "visible light phosphor B") which is excited by light from a solid light source and emits light having a peak wavelength within a range of 430 nm to less than 500 nm, and phosphor C (hereinafter referred to as "visible light phosphor C") which is excited by light from a solid light source and emits light having a peak wavelength within a range of 500 nm to less than 700 nm. Phosphors A to C preferably have maximum peak wavelengths within the above ranges, respectively. In order to more reliably present a broadband emission spectrum, the visible light phosphor preferably includes one or more phosphors A to C. It should be noted that the peak wavelength of the visible light phosphor can be adjusted to any wavelength within each region by adjusting the content of the activator of the visible light phosphor and adjusting the mixing ratio of the mixture.

[0065] Examples of the visible light phosphor A include: π-electron conjugated organic phosphor A1 (hereinafter also referred to as “visible light phosphor A1”), europium-activated oxysulfide phosphor, and silver-activated zinc sulfide phosphor (hereinafter also referred to as “visible light phosphor A2”), and one or more selected from them can be used.

[0066] Examples of the visible light phosphor A1 include a phosphor represented by the following formula (A1) having a π-electron conjugated system substituent at the 2- and 5-positions of the 1,3,4-oxadiazole ring.

[0067]

[0068] R1(π) and R2(π) are hydrogen or π-electron conjugated system substituents, for example, phenyl, biphenyl, naphthyl, carbazolyl, pyridyl, bipyridyl. In addition, these π-conjugated system substituents may have substituents such as alkyl groups having 1 to 10 carbon atoms, halogen atoms, etc. As examples of alkyl groups having 1 to 10 carbon atoms, methyl, ethyl, propyl, isopropyl, dimethylpropyl, tert-butyl, n-butyl, isobutyl, pentyl, etc. can be mentioned.

[0069] The visible light phosphor A1 may be, for example, a π-electron conjugated organic phosphor including 1 to 3 1,3,4-oxadiazole rings (-C2N2O-), 1,4-benzene rings (-C6H4-) and 1-benzene rings (-C6H5). The purity of the visible light phosphor A1 is preferably 90% or more. The visible light phosphor A1 may be one or more selected from these.

[0070] Examples of the visible light phosphor A2 include a mixture of a europium-activated oxysulfide phosphor (A2-1) and a silver-activated zinc sulfide phosphor (A2-2).

[0071] Examples of the europium-activated oxysulfide phosphor (A2-1) include an oxysulfide phosphor having at least one rare earth metal selected from the group consisting of gadolinium, yttrium and lanthanum, and oxysulfide as a matrix crystal, and containing europium as an activator in the matrix crystal.

[0072] The europium-activated oxysulfide phosphor can also be a phosphor represented by the following formula (A2-1).

[0073] (A 2-x ,Eu x )2O2S...(A2-1)

[0074] (A is any one of Ga, Y, and La, and x is a number satisfying 0<x<0.1.)

[0075] The silver-activated zinc sulfide phosphor (A2-2) can also be a phosphor represented by the following formula (A2-2).

[0076] (Zn 1-x ,Ag 2x )S...(A2-2)

[0077] (Wherein, x is a number satisfying 0<x<0.1.)

[0078] In the visible light phosphor A2, the mixing ratio of the europium-activated oxysulfide phosphor (A2-1) and the silver-activated zinc sulfide phosphor (A2-2) can be set to 0.1 or more and 9 or less in the form of mass ratio [(A2-1) / (A2-2)].

[0079] Examples of the visible light phosphor B include europium-activated alkaline earth aluminate phosphors. Examples of the europium-activated alkaline earth aluminate phosphors include phosphors that use aluminates of one or more Group 2 elements selected from the group consisting of calcium, strontium, magnesium, and barium as a matrix crystal, and contain europium as an activator in the matrix crystal. As the visible light phosphor B, one or more selected from these can be used.

[0080] The visible light phosphor B can also be a phosphor represented by the following formulas (B1) to (B4).

[0081] (A 1-x ,Eu x )Al 11 O 17 ...(B1)

[0082] (Wherein, A is Ca, Sr, Mg, Ba or a combination thereof, and x is a number satisfying 0<x<0.1.)

[0083] (Sr 0～0.8 Si6N8:Eu 0.01～0.2 ...(B2)

[0084] (Ca 0.25～2 Si 0.01～11.49 Al 0.51～11.99 O 0.01～11.49 N 4.51～15.99 ): Ce 0.001～0.5 ...(B3)

[0085] Al 4.6 Si 0.3～0.39 N5:Eu 0.01～0.1 ...(B4)

[0086] Examples of the visible light phosphor C include europium-activated strontium silicate phosphors. Examples of the europium-activated strontium silicate phosphors include visible light phosphors C1 to C5, which are phosphors having strontium silicate as a matrix crystal and the matrix crystal containing europium as an activator, and are represented by the following formulas (C1) to (C5).

[0087] (Sr 1-x ,Eu x )3SiO5...(C1)

[0088] (Wherein, x is a number satisfying 0<x<0.1.)

[0089] (Sr 1-x-y ,Ba x ,Eu y )3SiO5...(C2)

[0090] (x, y are numbers satisfying 0<x<1, 0<y<0.1.)

[0091] (Sr 1-x-y ,Ba x ,Eu y )2SiO4...(C3)

[0092] (x, y are numbers satisfying 0<x<1, 0<y<0.1.)

[0093] Me2Si5N8:Eu...(C4)

[0094] MeAlSiN3:Eu...(C5)

[0095] However, in formula (C4) and (C5), Me represents Ca, Sr, or Ba.

[0096] As the visible light phosphor C, one or more selected from the above-mentioned visible light phosphors C1 to C5 can be used.

[0097] The total content of the phosphor in each layer is preferably 3% by mass or more and 75% by mass or less, and more preferably 5% by mass or more and 60% by mass or less. By setting it within the above range, a homogeneous layer can be formed with good dispersibility, and the light emission from the phosphor can be effectively obtained, while achieving the condition of suppressing the dissipation of light generated by scattering in the layer, so that sufficient light emission intensity and narrow radiation angle characteristics can be obtained.

[0098] The content of the visible light phosphor can be selected according to the desired light balance of each wavelength. For example, the content of phosphor A is preferably 2% by mass or more and 50% by mass or less of all phosphors contained in the fluorescent film, and more preferably 5% by mass or more and 35% by mass or less. The content of phosphor B is preferably 2% by mass or more and 50% by mass or less of all phosphors contained in the fluorescent film, and more preferably 5% by mass or more and 35% by mass or less. The content of phosphor C is preferably 1% by mass or more and 30% by mass or less of all phosphors contained in the fluorescent film, and more preferably 5% by mass or more and 15% by mass or less.

[0099] In the case of a light-emitting device having a continuous emission spectrum at least in the range of 400 nm to 1000 nm, the number of phosphors contained in the phosphor film can be a combination of a visible light phosphor and the above-mentioned near-infrared phosphor, and the total number of phosphors can be 2 or more, preferably 3 or more, and more preferably 5 or more. There is no particular limitation on the upper limit, and it can be 10 or less or 8 or less.

[0100] When the fluorescent film is composed of a plurality of layers, the number of types of fluorescent bodies contained in each layer is preferably 1 or more and 4 or less, and more preferably 1 or more and 3 or less. By setting the number of types of fluorescent bodies to 1 or more and 4 or less, it is possible to prevent the dispersibility of the fluorescent bodies from being reduced by including a plurality of fluorescent bodies having different specific gravities and particle sizes.

[0101] The fluorescent film is composed of one or more layers, preferably a plurality of layers containing different types of fluorescent bodies. By being composed of a plurality of layers containing different types of fluorescent bodies, the types of fluorescent bodies contained in one layer will not become too many, so the dispersion of the fluorescent bodies can be improved to form a uniform fluorescent film. The number of layers constituting the fluorescent film can be set to 1 or more, 2 or more, or 3 or more, and can be set to 8 or less, 7 or less, or 5 or less.

[0102] It should be noted that "the type of phosphor" refers to the type that is distinguished according to the peak wavelength of the phosphor. Even if the mother crystal is the same and the constituent elements of the mixture are the same, the phosphors with different peak wavelengths due to the addition amount of the activator, the mixing ratio of the constituent elements of the mixture, etc. are different types. "Multiple layers (two or more layers) of different types of phosphors" means that at least one phosphor contained in a certain layer is inconsistent with the type of phosphors contained in other layers. In terms of efficiently making a fluorescent film that can present a broadband emission spectrum, it is preferred that the types of phosphors contained are all different between each layer. In terms of making "multiple layers of different types of phosphors", for example, it can be composed of two layers including a layer containing a near-infrared phosphor and a layer containing visible light phosphors A to C. Alternatively, it is also possible to make multiple layers of different types of phosphors by constituting a layer including a near-infrared phosphor, a layer including a visible light phosphor A, a layer including a visible light phosphor B, and a layer including a visible light phosphor C. It is also possible to stack layers as other layers according to the type of phosphor.

[0103] However, the light of phosphors having peak wavelengths in the ultraviolet region and the visible light region close to the ultraviolet region tends to disappear due to reabsorption by other phosphors. Therefore, in the case where the fluorescent film includes the visible light phosphor A and the visible light phosphor B, it is preferable that the visible light phosphor A and the visible light phosphor B are included in different layers for the purpose of preventing photoinactivation while obtaining light emission on the short wavelength side with sufficient intensity. On the other hand, the near-infrared phosphor and the visible light phosphor C will not have a significant effect on the intensity of the emission spectrum even if they are mixed with other phosphors.

[0104] When the fluorescent film is formed of a plurality of layers of different types of fluorescent materials, the plurality of layers are stacked in the direction of travel of light from the solid-state light source in the order from the layer containing the fluorescent material with a longer peak wavelength to the layer containing the fluorescent material with a shorter peak wavelength. By forming such a structure, it is possible to prevent the light that has emitted fluorescent light from being used to excite the fluorescent material contained in the next layer, thereby preventing the light with a short wavelength from disappearing.

[0105] The thickness of each layer of the fluorescent film can be adjusted according to the proportion of the phosphor contained. For example, when the content of the phosphor is greater than 5 mass % and less than 60 mass %, it can be set to greater than 1 μm and less than 500 μm. When the content of the phosphor is more than 60 mass %, it can be set to greater than 10 μm and less than 100 μm.

[0106] There is no particular limitation on the method for making the fluorescent film. For example, it can be made by the following method: using a known stirring and mixing device, the above-mentioned fluorescent body and a dispersant such as silicone nanopowder as needed are dispersed in a thin film material such as silicone resin, epoxy resin, ethyl cellulose, glass, etc. and made into a paste, and then applied or printed on a solid light source or a transparent substrate such as a glass plate by potting, spraying, spin coating, screen printing, gravure printing, etc. There is no particular limitation on the mixing method when mixing multiple fluorescent bodies, and the mixing method can be carried out using a conventional mixing device. In the case where the fluorescent film is composed of multiple layers, each layer can be joined with silicone resin, epoxy resin, etc., or fixed by pressing with a fixing component. Regarding the joining method when the fluorescent film is assembled in a package, it can also be joined with silicone resin, epoxy resin, etc., or fixed by pressing with a fixing component.

[0107] (Light-emitting device)

[0108] The light-emitting device of the present embodiment preferably has a continuous emission spectrum (hereinafter also referred to as a "continuous spectrum") at least in the range of 400 nm and 1000 nm. By having a continuous spectrum within this range, it can be preferably used as a light source for industrial machines that require broadband light emission. "Continuous emission spectrum" refers to the entire region within this range, and the luminous intensity of the luminous spectrum (hereinafter also referred to as "fluorescence intensity") is 0.01 or more (1% or more) relative to the 800nm ​​reference. In the entire region of the above-mentioned range, it is 1% or more relative to the 800nm ​​reference, so it can be more preferably used as a light source for industrial machines. When used as a standard light source, in the entire region of the above-mentioned range, the luminous intensity (fluorescence intensity) of the luminous spectrum is preferably 0.015 or more (1.5% or more) relative to the 800nm ​​reference, and from the viewpoint of ease of use, it is more preferably 0.05 or more (5% or more).

[0109] For example, in Figure 6 In the spectrum of Example 1 shown, the fluorescence intensity at both ends of the continuous spectrum (350nm, 1200nm) is 1.7% and 1.9% respectively relative to the maximum intensity near 800nm, and the fluorescence intensity at the minimum point near 390nm is also 8.2%, both exceeding 1.5%, which can be said to have a continuous emission spectrum in the range of 350nm to 1200nm. Therefore, this light-emitting device has a continuous emission spectrum in the range of at least 400nm to 1000nm, and can be fully used as a standard light source for industrial equipment.

[0110] The light emitting device can be configured to have a continuous spectrum with a wider band by using the emission spectrum of the solid light source and the near-infrared phosphor used. For example, when a solid light source that emits light with a peak wavelength in a range below 410 nm is used as the solid light source, if the half-maximum full width of the emission spectrum is set to be above 50 nm, a light emitting device having a continuous spectrum in a range of at least 360 nm can be manufactured.

[0111] In addition, by using the near-infrared phosphor of this embodiment, a broadband continuous spectrum including a region exceeding 1200 nm can be realized. In the examples described below, examples of light-emitting devices having a continuous emission spectrum in a range of at least 350 nm to 1200 nm are shown.

[0112] The light emitting device has a peak wavelength in the near infrared region exceeding 700nm. When a strong amount of light is required in the near infrared region, a wavelength that obtains the maximum luminous intensity in the continuous luminous spectrum presented by the light emitting device is provided in the near infrared region exceeding 700nm. When light emission on the higher wavelength side is required, by adjusting the composition and mixing ratio of the near infrared phosphor, it is also possible to construct it in a manner having a peak wavelength in the range of more than 750nm or more than 800nm. By having a peak wavelength in the near infrared region, light with a wider wavelength range than conventional LEDs can be obtained, and therefore it can be more suitable as a light emitting device for industrial machines such as spectroscopic analysis devices.

[0113] Examples of the industrial equipment include spectroscopic analysis equipment such as a white interference film thickness meter and a handheld colorimeter, and industrial equipment using a halogen lamp.

[0114] The white interference film thickness meter ideally contains a plurality of fringes (interference fringes) within the wavelength band of the light source, and therefore, in particular, a light source with a wider bandwidth is required for measuring the thickness of an extremely thin film. Conventional LED light sources cannot achieve a sufficiently wide bandwidth, but the light emitting device according to this embodiment can achieve a sufficient wavelength band as a light source for a white interference film thickness meter.

[0115] Handheld colorimeters currently set the photometric range to 400nm to 700nm in accordance with the frequency band of the light source. However, the XYZ colorimetric system established by the International Commission on Illumination (CIE) stipulates that it is 380nm to 780nm, so it is difficult to perform rigorous measurements with previous handheld colorimeters. If the light-emitting device according to this embodiment has a wide-band luminous spectrum in the range of at least 400nm and less than 1000nm, it can achieve correct measurements in accordance with the regulations of CIE. As a result, it can contribute to a wide range of industries such as the lighting field, color field, printing field, and coating field.

[0116] Halogen lamps are used as light sources for many industrial machines. However, halogen lamps used in spaces isolated from the outside, such as clean rooms, may have problems with heat generation and heat dissipation. The light-emitting device according to this embodiment can be adjusted to have a light emission spectrum similar to that of a halogen lamp, and can therefore be suitably used as a substitute for a halogen lamp. When used as a substitute for a halogen lamp, a light-emitting device having a light emission spectrum similar to that of a halogen lamp can be produced by combining a plurality of the above-mentioned phosphors.

[0117] <Modification>

[0118] Next, a modification of the light emitting device of this embodiment will be described. In each of the following modifications, only the differences from the first embodiment and other modifications will be described. Configurations not described below can be the same as those already described.

[0119] (First Modification)

[0120] The first modification is an example in which the fluorescent film is formed of a plurality of layers in the first embodiment (see Figure 2 ) is a variation of the present invention, which is constructed in a manner such that a plurality of regions having different types of phosphors contained therein are provided on the same surface.

[0121] use Fig. 9 , 10 The first modification example will be described. Fig. 9 is a schematic plan view showing a configuration example of a light emitting device according to a first variant. Fig.10 It is a schematic side view. Fig. 9 , 10 The light emitting device 100 shown comprises: a solid light source 21 provided on a package 11, and fluorescent films 30, 31 provided in a manner covering the solid light source 21. The fluorescent film 30 has two or more regions (regions 30a to 30f) containing different types of fluorescent bodies. As described above, the "type of fluorescent body" refers to a type distinguished by the peak wavelength of the fluorescent body. It should be noted that, in this example, the fluorescent films 30, 31 are provided on a substrate 7, but the substrate 7 is not a necessary component. As a substrate, a transparent member such as glass can be used. By using such a substrate 7, film formation is easy, handling is easy, and strength can be maintained.

[0122] In addition, in this example, an example of a case where the fluorescent film 30 and other fluorescent films 31 are stacked is shown, but it is also possible to use only a single-layer fluorescent film 30. When a single-layer fluorescent film 30 is used, it is configured so that a near-infrared fluorescent material is contained in at least one region. In this case, the fluorescent film 30 preferably has: a region (for example, region 30a) containing at least one near-infrared fluorescent material, and a region (for example, regions 30b to 30f) containing at least one visible light fluorescent material. When the fluorescent film 30 does not contain a near-infrared fluorescent material, it is sufficient to stack the fluorescent film 30 and the fluorescent film 31 containing at least one near-infrared fluorescent material. The configuration of the other fluorescent film 31 is not particularly limited, and it may be a fluorescent film having two or more regions with different types of fluorescent materials contained on the same surface (the same configuration as the fluorescent film 30), or it may be a fluorescent film consisting of one region containing one or more fluorescent materials.

[0123] When the fluorescent film 30 and the other fluorescent film 31 are stacked, it is preferable to stack the layers in the direction of travel of light from the solid-state light source in the order from the fluorescent film containing the fluorescent body with a longer peak wavelength to the fluorescent film containing the fluorescent body with a shorter peak wavelength, as in the case of forming a plurality of layers in the first embodiment. By forming such a structure, it is possible to prevent the fluorescent light from being used to excite the fluorescent body contained in the next fluorescent film and causing the light with a short wavelength to disappear.

[0124] Fig. 9 In the figure, the fluorescent film 30 is composed of 6 regions 30a to 30f, but the number of regions is not limited thereto and can be any number of 2 or more. In order to prevent the disappearance of the fluorescent light, it is preferably composed of 4 or more regions containing different types of fluorescent substances.

[0125] The method for producing the fluorescent film 30 is not particularly limited, and the fluorescent film 30 can be produced by printing with ink containing fluorescent material or by arranging individual fluorescent films produced by mixing fluorescent material and resin in advance on the same surface.

[0126] (Second Modification)

[0127] The second modification is an example of using two or more solid light sources. Fig.11 , 12 The second modification example will be described. Fig.11 , 12 It is a schematic plan view showing a configuration example of a light emitting device according to a second variant. Fig.11 The light emitting device 101 shown includes two or more solid light sources 22a to 22f provided on the same surface of a package 12, and fluorescent films 32a to 32e covering one or more of the solid light sources 22a to 22f. Fig.12The light emitting device 102 shown includes solid light sources 23a to 23f, a fluorescent film 33g covering all of the solid light sources 23a to 23f, and a fluorescent film 33a to 33f provided on the fluorescent film 33g and at a position covering one of the solid light sources 23a to 23f.

[0128] The solid light sources 22a to 22f and 23a to 23f may be solid light sources that emit light of the same peak wavelength, or may be solid light sources that emit light of different peak wavelengths. Fig.11 , 12 In the figure, the solid light source is composed of 6 solid light sources 22a~22f or 23a~23f, but the number of solid light sources is not limited to this and can be set to any number that can cope with the required brightness, such as 2 or more, 3 or more, 5 or more, 10 or more.

[0129] The composition of the fluorescent film covering each solid light source is not limited to Fig.11 , 12 The structure shown can cover each solid light source with a different fluorescent film (preferably a fluorescent film containing different types of fluorescent bodies), or can cover a part or all of the solid light sources with a single fluorescent film. In either case, at least one fluorescent film is constructed in a manner that contains at least a near-infrared fluorescent body. In the case of covering each solid light source with a different fluorescent film, it is preferred that at least one fluorescent film other than the fluorescent film containing at least a near-infrared fluorescent body is a fluorescent film containing at least one selected from the above-mentioned visible light fluorescent bodies. In the case of covering each solid light source with a single fluorescent film, it is preferred that the fluorescent film contains a near-infrared fluorescent body and a visible light fluorescent body. In addition, the fluorescent film having two or more regions on the same surface described in the first variant can also be used, and a fluorescent film having a plurality of layers can also be used. The structure of this case is as described above.

[0130] The method for producing the fluorescent film is not particularly limited, and the fluorescent film can be produced by the same method as the above-mentioned production method.

[0131] In the case of a structure having a plurality of fluorescent films on the same plane (for example, a structure in which each solid light source is covered with a different fluorescent film), from the perspective of preventing the resin from flowing out when heating is performed to cure the resin, a so-called dam such as a silicone resin may be provided in a manner surrounding the solid light source.

[0132] (Other components)

[0133] The light emitting device may be provided with a lens in a manner covering the solid light source and the fluorescent film in order to control the directivity of the emitted light. Examples of the lens include a single-sided convex lens, a double-sided lens, a convex meniscus lens, a rod lens, and an optical fiber.

[0134] In addition, the light emitting device may be subjected to blasting on the light incident surface and the light exit surface of the lens for the purpose of mixing lights of different wavelengths. The blasting method is not particularly limited, and it can be performed by a known sandblasting method or the like.

[0135] [Example]

[0136] The present invention will be described in more detail below with reference to Examples, but the present invention should not be construed as being limited to these Examples.

[0137] [Manufacturing Examples 1 to 14] (Manufacturing of near-infrared phosphor)

[0138] In the embodiment, a composition of Li a Sr b La c Si d N e Eu f (wherein a to f are numbers satisfying a+b+c+d+e+f=100) an infrared phosphor material is represented.

[0139] Near-infrared phosphors P1 to P14 that can be used in the examples were produced in the following manner. Table 1 shows the designed compositions of these phosphors.

[0140] Table 1

[0141] Si N Li Sr La Eu Phosphor P1 37.74 55.60 0.00 4.11 1.66 0.89 Phosphor P2 37.32 56.09 0.00 0.77 4.94 0.88 Phosphor P3 34.18 54.42 0.00 7.63 2.85 0.91 Phosphor P4 33.54 55.27 0.00 1.90 8.39 0.89 Phosphor P5 31.07 53.39 0.00 10.72 3.88 0.93 Phosphor P6 30.29 54.57 0.00 2.88 11.36 0.91 Phosphor P7 24.41 51.18 0.00 17.33 6.10 0.98 Phosphor P8 38.09 55.19 2.24 2.46 1.12 0.90 Phosphor P9 37.81 55.52 2.22 0.22 3.34 0.89 Phosphor P10 34.73 53.69 3.86 4.86 1.93 0.93 Phosphor P11 34.29 54.28 3.81 0.99 5.72 0.91 Phosphor P12 31.75 52.36 5.29 6.99 2.65 0.95 Phosphor P13 31.20 53.19 5.20 1.66 7.80 0.94 Phosphor P14 25.27 49.47 8.42 11.62 4.21 1.01

[0142] In order to obtain the phosphor of the above-designed composition, the raw material powders Si3N4, Li3N, Sr3N2, LaN, and EuN were weighed at the weight ratio shown in Table 2 and mixed with an agate pestle and mortar for 10 minutes. Thereafter, the obtained mixture was filled into a crucible made of boron nitride. It should be noted that all the steps of weighing and mixing the powders were carried out in a glove box in a nitrogen environment capable of maintaining a moisture content of less than 1 ppm and an oxygen content of less than 1 ppm.

[0143] Table 2 (wt%)

[0144] <![CDATA[Si3N4]]> <![CDATA[Li3N]]> <![CDATA[Sr3N2]]> LaN E Phosphor P1 68.80 0.00 15.53 9.93 5.75 Phosphor P2 64.14 0.00 2.74 27.76 5.36 Phosphor P3 54.64 0.00 25.30 14.89 5.17 Phosphor P4 49.27 0.00 5.79 40.28 4.66 Phosphor P5 44.82 0.00 32.08 18.33 4.77 Phosphor P6 39.52 0.00 7.79 48.48 4.21 Phosphor P7 29.14 0.00 42.90 23.82 4.14 Phosphor P8 75.27 1.10 10.10 7.24 6.29 Phosphor P9 71.49 1.04 0.87 20.63 5.97 Phosphor P10 62.73 1.73 18.21 11.40 5.94 Phosphor P11 57.90 1.60 3.47 31.56 5.48 Phosphor P12 53.28 2.21 24.32 14.53 5.67 Phosphor P13 48.16 1.99 5.33 39.39 5.13 Phosphor P14 36.71 3.04 35.02 20.01 5.21

[0145] Then, a crucible made of boron nitride containing the mixed powder was placed in an electric furnace of graphite resistance heating. The sintering operation was performed as follows: First, the sintering environment was made into a vacuum by a diffusion pump, and the temperature was raised from room temperature to 800°C at a rate of 1200°C per hour. At 800°C, nitrogen with a purity of 99.999% by volume was introduced and the pressure was set to 0.92 MPa. The temperature was raised from 600°C per hour to a sintering temperature of 1700°C, and the sintering temperature was maintained at 1700°C for 2 hours. After sintering, the mixture was crushed by hand using a mortar to obtain infrared phosphor powders P1 to P14.

[0146] The emission characteristics of this phosphor when excited by a Xe light source with a spectrum at 370 nm are shown in Table 3. In Table 3, "emission peak wavelength" means "maximum peak wavelength" and the unit of emission half-width is "nm".

[0147] Table 3

[0148] Peak emission wavelength (nm) Full Width at Half Maximum Relative Strength Excitation peak wavelength (nm) Phosphor P1 797 290 416 443 Phosphor P2 811 193 219 443 Phosphor P3 808 212 482 448 Phosphor P4 819 201 305 445 Phosphor P5 631 276 636 446 Phosphor P6 809 199 323 441 Phosphor P7 716 164 465 442 Phosphor P8 776 288 486 441 Phosphor P9 825 203 239 519 Phosphor P10 809 203 444 443 Phosphor P11 839 218 190 443 Phosphor P12 816 202 494 499 Phosphor P13 817 200 234 441 Phosphor P14 633 121 147 448

[0149] Figure 3 , 4 The emission spectra of the above-mentioned phosphors P1 to P14 are shown in FIG. Figure 3 , 4 In the figure, the horizontal axis represents the wavelength (nm) and the vertical axis represents the fluorescence intensity (arbitrary unit). It should be noted that the spectrum measurement uses MCPD9800 (311C model) manufactured by Otsuka Electronics. Here, the case of excitation with a xenon lamp with a spectral distribution of 370nm is shown, but these phosphors can be excited in a wide wavelength range of 300 to 500nm. The same luminescence spectrum can be obtained even if the excitation wavelength is changed. These phosphors have a luminescence peak (peak wavelength) in the range of 700 to 850nm, and have a luminescence spectrum covering a wide range of the near-infrared region. These phosphors use divalent Eu as the luminescent ion and have a wide luminescence spectrum with a half-width of more than 100nm produced by the 5d-4f transition. The luminescent ions of the further manufactured phosphor are in a plurality of coordination environments, so they exhibit a spectrum with several luminescence peaks overlapping. Therefore, the luminescence spectrum line width is wider than that of the general 5d-4f transition type phosphor. As shown in this manufacturing example, a half-width of 100 to 300nm can be obtained. The balance of the intensities of the plurality of emission peaks differs depending on the manufacturing composition. Some have a maximum peak below 700 nm, but are characterized by overlapping sub-peaks in the wavelength region above 700 nm.

[0150] According to the above manufacturing example, Li a Sr b La c Si d Ne Eu f A phosphor having a composition of (wherein, a+b+c+d+e+f=100, 0≤a≤8.22, 0.22≤b≤17.33, 1.12≤c≤11.36, 22.41≤d≤38.09, 49.47≤e≤56.09, 0.88≤f≤1.01) is used in an embodiment of the present invention. However, the concentration of the luminescent ion Eu is set to about 1 atm%, but can be set to the range used in general phosphors, that is, 0.01 to 10 atm%. By setting it to the above-mentioned design range, the reduction in luminous intensity can be suppressed, and it can be used more preferably as a light-emitting element for industrial machinery.

[0151] In the following examples, the light-emitting element is made using the phosphor P8 in the above manufacturing example. This phosphor has a wide emission line width and high emission intensity, so it can be said to be particularly suitable for light-emitting elements, but the purpose of the present invention can be achieved even if phosphors of other compositions are used.

[0152] The emission spectrum of the near-infrared phosphor P8 was measured using a spectrometer (light source: a xenon lamp that splits at 370 nm), and the peak wavelengths were measured at 680±3 nm and 776±3 nm. Figure 5 .

[0153] The following phosphors were used as visible light phosphors.

[0154] [Visible light phosphor A1] A phosphor represented by formula (A1-1) (molecular formula: C 24 H 22 N2O), peak wavelength 405nm±3nm

[0155]

[0156] [Visible light phosphor A2] A mixture of Y2O2S:Eu and ZnS:Ag, with a peak wavelength of 424±3nm

[0157] [Visible light phosphor B]BaMgAl 11 O 17 :Eu, peak wavelength 452±3nm, 459±3nm

[0158] [Visible light phosphor C1-1] Sr3SiO5:Eu, peak wavelength 520±3nm

[0159] [Visible light phosphor C1-2] Sr3SiO5:Eu, peak wavelength 593±3nm

[0160] [Adhesive] Silicone resin, Shin-Etsu Chemical Co., Ltd. "KER-1930"

[0161] [Dispersant] Silicone nanopowder, manufactured by Tokuyama Co., Ltd., Japan, "REOLOSIL"

[0162] [Example 1]

[0163] Using a stirring device, the phosphor powder and silicone resin shown in Table 4 were mixed in the ratio described in Table 1 to prepare phosphor resin compositions a to e. The resin composition a was formed into a film by sliding a scraper with a gap between the scraper and the substrate on a transparent substrate manufactured by SCHOTT, and after thermal curing, it was peeled off from the transparent substrate to form the first layer having the thickness described in Table 1. Next, the resin composition b was formed into the second layer in the same manner as the first layer. Furthermore, the third, fourth, and fifth layers were formed using resin compositions c, d, and e in the same manner, and silicone resin was thinly applied between the layers to overlap them, thereby preparing a 5-layer fluorescent film in which the five types of phosphors are contained in different layers.

[0164] On the bottom surface of the recessed ceramic package, apply a chip adhesive made of silver paste, and mount an ultraviolet LED chip with a peak wavelength at 365nm (1.1mm×1.1mm×height 0.2mm, current value 500mA, radiation flux 600mW or more) on it. Connect the positive and negative electrodes of the LED chip to the positive and negative electrode pads of the package with gold wires. Arrange an electrostatic protection element in parallel with the LED chip. Use silicone resin to install the above-mentioned fluorescent film in the opening of the recessed portion of the package to make a Figure 1 , 2 A light emitting device of the structure shown.

[0165] Table 4

[0166]

[0167] [Example 2]

[0168] A light-emitting device was produced in the same manner as in Example 1 except that the fluorescent film was produced with the composition and ratio shown in Table 5. The fluorescent film in this light-emitting device had a seven-layer structure in which seven kinds of fluorescent materials were contained in different layers.

[0169] Table 5

[0170]

[0171] [Example 3]

[0172] A light-emitting device was produced in the same manner as in Example 1 except that the fluorescent film was produced with the composition and ratio shown in Table 6. The fluorescent film in this light-emitting device had a three-layer structure in which the visible light phosphors A and B were contained in different layers, and the near-infrared phosphor and the visible light phosphors C1-1 and C1-2 were contained in the same layer.

[0173] Table 6

[0174]

[0175] [Comparative Example 1]

[0176] A light-emitting device was produced in the same manner as in Example 1 except that the near-infrared phosphor was not included.

[0177] [Comparative Example 2]

[0178] A light-emitting device was produced in the same manner as in Example 1 except that a phosphor "BR-101 / N" (peak wavelength 648 nm, full width at half maximum 88 nm) manufactured by Mitsubishi Chemical Corporation was used instead of the near-infrared phosphor.

[0179] [Luminescence spectrum]

[0180] The emission spectra of the light emitting devices of the examples and comparative examples were measured using a spectrometer under the conditions of Ta = 25°C and IF = 500 mA. The results of Examples 1 and 3 are shown in FIG. Figure 6 The results of Example 2 are shown in Figure 7 The comparison between Comparative Examples 1 and 2 and Example 1 is shown in Figure 8 .

[0181] like Figure 6 , 7 As shown, the light emitting devices of Examples 1 to 3 have peak wavelengths in the region exceeding 780 nm. Among them, the light emitting devices of Examples 1 and 3 have wavelengths that give the maximum light emission intensity in the continuous light emission spectrum in the region exceeding 780 nm.

[0182] In addition, Figure 6 In the spectrum of Example 1 shown, the fluorescence intensity at the two ends of the continuous spectrum (350nm, 1200nm) is 1.7% and 1.9% respectively relative to the maximum intensity near 800nm, and the fluorescence intensity at the minimum point near 390nm is also 8.2%, both exceeding 1.5%. Therefore, this light-emitting device has a continuous emission spectrum at least in the range of 350nm and 1200nm. Similarly, the light-emitting devices of Examples 2 and 3 have also been confirmed to have a continuous emission spectrum in a wide band of at least 350nm and 1200nm.

[0183] In addition, the light-emitting device shown in the embodiment has been confirmed to achieve a radiant flux of more than 10 mW. Therefore, this light-emitting device has a wide-band luminous spectrum distribution from the ultraviolet region to the near-infrared region, and has high brightness and high optical concentration. The luminous response when powered on, the temporal variation of luminous intensity, and the wavelength shift caused by temperature are also small. Therefore, it can be used as a replacement element for the previous light source (halogen lamp, etc.) that has problems related to these characteristics, and is suitable for use in a light-emitting device for industrial machinery.

[0184] Description of Reference Numerals

[0185] 10, 100, 101, 102 light emitting device;

[0186] 1, 11, 12, 13 package;

[0187] 2, 21, 22a-22e, 23a-23f solid light sources;

[0188] 3, 30, 31, 32a-32e, 33a-33g fluorescent film;

[0189] 4 wires;

[0190] 5 electrode pads;

[0191] 6. Electrostatic protection components.

Claims

1. A light emitting device, wherein: The invention comprises at least: a solid light source emitting light having a peak wavelength in a range of 480 nm or less, and a fluorescent film covering the solid light source and containing at least one fluorescent substance, The fluorescent film contains: at least one near-infrared fluorescent substance which is excited by the light from the solid light source and emits light having a peak wavelength in a range exceeding 700 nm and a full width at half maximum of a light emission spectrum in a range including the peak wavelength of 100 nm or more, The near-infrared phosphor has a composition represented by the following formula (I): them a Sr. b to c And d N e I f ...(I), a~f are numbers satisfying a+b+c+d+e+f=100, 0≤a≤8.22, 0.22≤b≤17.33, 1.12≤c≤11.36, 22.41≤d≤38.09, 49.47≤e≤56.09, and 0.88≤f≤1.

01.

2. The light emitting device according to claim 1, wherein: It has a continuous emission spectrum at least in the range of 400 nm to 1000 nm.

3. The light emitting device according to claim 1 or 2, wherein: The fluorescent film further includes at least one visible light phosphor that is excited by the light from the solid light source and emits light having a peak wavelength in a range of 350 nm to 700 nm.

4. The light emitting device according to claim 3, wherein: The fluorescent film respectively contains one or more visible light phosphors A, visible light phosphors B, and visible light phosphors C as the visible light phosphors, the visible light phosphor A is excited by the light from the solid light source to emit light with a peak wavelength in the range of greater than 350nm and less than 430nm, the visible light phosphor B is excited by the light from the solid light source to emit light with a peak wavelength in the range of greater than 430nm and less than 500nm, and the visible light phosphor C is excited by the light from the solid light source to emit light with a peak wavelength in the range of greater than 500nm and less than 700nm.

5. The light emitting device according to claim 4, wherein: The fluorescent film is formed of two or more layers, and the visible light phosphors A and B are contained in different layers.

6. The light emitting device according to claim 4, wherein: The fluorescent film is formed of two or more layers containing different types of fluorescent substances. The two or more layers are stacked in the direction of travel of light from the solid-state light source in order from a layer containing a phosphor having a longer peak wavelength to a layer containing a phosphor having a shorter peak wavelength.

7. The light emitting device according to claim 5, wherein: The number of types of the phosphor contained in each layer of the fluorescent film is 1 or more and 3 or less.

8. The light emitting device according to claim 4, wherein: The fluorescent film has two or more regions containing different types of the fluorescent material on the same surface.

9. The light emitting device according to claim 8, wherein: The two or more regions having different types of phosphors include at least a region containing the near-infrared phosphor and a region containing the visible light phosphor.

10. The light emitting device according to claim 1 or 2, wherein: Two or more of the solid light sources are provided.

11. The light emitting device according to claim 1 or 2, wherein: The solid light source is at least one selected from a light emitting diode, a laser diode, and an organic electroluminescent element.

12. The light emitting device according to claim 1 or 2, wherein: The near-infrared phosphor contains divalent europium.

13. A fluorescent film, wherein: The invention comprises: at least one near-infrared phosphor which emits light having a peak wavelength in a range exceeding 700 nm and having a full width at half maximum of 100 nm or more in a range including the peak wavelength by means of light having a peak wavelength in a range below 480 nm; and at least one visible light phosphor which emits light having a peak wavelength in a range between 350 nm and 700 nm or less by means of the light having a peak wavelength in a range below 480 nm, The near-infrared phosphor has a composition represented by the following formula (I): them a Sr. b to c And d N e I f ...(I), a~f are numbers satisfying a+b+c+d+e+f=100, 0≤a≤8.22, 0.22≤b≤17.33, 1.12≤c≤11.36, 22.41≤d≤38.09, 49.47≤e≤56.09, and 0.88≤f≤1.01.

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